I'll try to answer your question, sorry if it doesn't satisfy you. While some credited Süleyman as the creator or compiler of the Kanun (Ottoman secular laws), it's somewhat incorrect. Sultan Bayezid II was the first one who ordered the compilation of all the kanuns of the empire, thus creating the Kanun-i Osmani. However, this first kanun was mostly about the obligations of the taxpayer (re'aya) and the timar holder and only included a handful of penal laws. These penal statutes were incorporated into the general law book because the punishment of criminals was the responsibility of the members of the military class and thus formed an integral part of the main theme of the secular law. However, penal statutes often appear in the law codes haphazardly, making it difficult to understand the legal procedure from arrest through punishment. This is where Süleyman came in, he brought Islamic and bureaucratic laws and punishments into harmony with each other and perfected the criminal code of the Kanun-i Osmani. Compared to only 52 penal statutes in Bayezid's law, Süleyman's has 93, and these additions didn't just elaborate and complete the older laws. They also deal with many offences not touched in the earlier codes at all, such as sodomy and other sexual perversions, false testimony, the forging of documents, the counterfeiting of coins, unfounded denunciation, disturbing public order and decency, and others. Furthermore, they also include many additional statutes on criminal procedure. Another change in the law is the structure of the penal code itself. Bayezid's laws divide penal codes into two, offences punishable by fines and/or strokes and those entailing capital or severe corporal punishment. Süleyman's code abolished this and arranged the statutes according to offences only and not, as before, according to penalties, making it more systematic than the older one. Süleyman's code wasn't the final version of the Ottoman law though, as later in the 17th century a new and the most comprehensive form of the Ottoman kanun law was compiled

Sources:

"The Studies of Old Ottoman Criminal Law" by Uriel Heyd